It is known to treat an endless belt of fabric for use, for example, in the forming section of a papermaking machine, in a manner such that a resinous material will substantially impregnate the fabric. In this connection reference is made to Christie et al, U.S. Pat. No. 3,252,821. Such a method has been useful in substantially entirely impregnating such fabrics. Heretofore, however, it has not been possible to selectively resin encapsulate select fibers of a multilayered papermakers' belt. Such select encapsulation would be desirable in the manufacture of papermakers belts such as, for example, multilayered papermakers press felts in which the base layer fibers are substantially entirely encapsulated with resin while the fibers of the surface layer are resin free thereby producing a felt having a compressible surface layer and relatively incompressible base layer. In this connection reference is made to Wicker, U.S. Pat. No. 3,214,327. In attempting to produce a press felt in which the degree of compressibility of the surface and base layers differs numerous manufacturing and fabricating problems have been encountered. For example, if resin-treated multifilament or staple yarns are used to form the base layer, I have found that it is difficult to weave and needle such yarns due to their hard and stiff character. To overcome the forementioned problem other avenues of solution have been attempted. For example, it is known to produce a felt using a base fabric which has been resin-treated subsequent to the weaving thereof. However, in needling a fibrous surface layer to such a resin treated base layer hardness of the resin coating causes high needle loom wear and short and variable needle life. In addition, the adhesion of the surface layer to the base layer, as well as the dimensional stability of such felts, has been found to be less than optimum. Uniformity of surface layer application has also been less than optimum which has made reproduceability difficult. Another avenue of solution has been to bond together adjacent fibers in a papermakers' belt by the use of swelling agents, solvents and thermoplastic fibers having a low melting point. In this connection reference is made to Hindle et al, British Pat. No. 963,212 and Ford, British Pat. No. 801,440. In some instances this has been done to the base layer of papermakers belt subsequent to the needling of a surface layer thereto. See for example Lindcroth, Swedish Pat. No. 307,728. However, heretofore I am not aware of it having been possible to control the degree of permeability and compressibility of such a belt by selectively resin encapsulating select fibers of the belt.
Accordingly, it is an object of the present invention to make multilayered papermakers' belts having improved surface layer adhesion characteristics.
It is also an object of the present invention to make multilayered papermakers' belts having a uniform fibrous surface layer.
It is another object of the present invention to make multilayered papermakers' belt having easy reproduceability.
It is a further object of the present invention to make a multilayered papermakers' belt having desirable abrasion resistance and improved wear characteristics.
It is still a further object of the present invention to make a multilayered papermakers' belt having excellent dimensional stability.
It is yet another object of the present invention to provide for the selective resin encapsulation of the fibers of a multilayered papermakers' belt.
Another object of the present invention is to facilitate the weaving of the base layer of a multilayered resin-treated papermakers' belt.
Yet another object of the present invention is to facilitate the needling of a multilayered papermakers' belt to prevent damage to the needles and to reduce needle loom wear.
A further object of the present invention is to selectively control the degree of permeability and compressibility of a papermakers' belt by resin application.